Prerequisites

• Python development libraries
  
  yum install python-devel
• setuptools
  Download EasyInstall and run it to install the appropriate setuptools egg for your Python version:
  cd /extra/src
wget http://peak.telecommunity.com/dist/ez_setup.py
python ez_setup.py
• Clearsilver
  Download and install Clearsilver, a fast, powerful, and language-neutral HTML template system:
  cd /extra/src
wget http://www.clearsilver.net/downloads/clearsilver-0.10.5.tar.gz
tar zxvf clearsilver-0.10.5.tar.gz
cd clearsilver-0.10.5
./configure
make
make install
cd python
python setup.py install
• SQLite
  Trac best supports SQLite, a self-contained, serverless, zero-configuration, transactional SQL database engine.
  Download the latest version (3.5.9 at time of writing):
  cd /extra/src
wget http://www.sqlite.org/sqlite-3.5.9.tar.gz
tar zxvf sqlite-3.5.9.tar.gz
cd sqlite-3.5.9

  Configure, build and install:

  ./configure
make
make install

  Ran into tcl errors when compiling on CentOS 4. Installing tcl-devel then reconfiguring and compiling took care of that:

  yum install tcl-devel

Trac installation
Latest version is 0.11.4 - install instructions need revising!!
Download the latest stable version from the Trac download page (0.10.4):

Install:

Configure Trac "environment"
Create a directory to contain all of the trac environments. The files need to be writeable by the apache anonymous user.

Creating a trac environment for the "dummy" project (from the subversion installation). Other than Project Name and Path to Repository (/var/svn/dummy), you can accept the defaults.

You can test Trac with the included tracd standalone server:

Then use your webbrowser to access http://yourserver:8000/. You should be able to access your test project. When you're done, quit tracd
0.10.4 -> 0.11.5 upgrade
Recommend doing this upgrade as there's a significant addition of a web admin interface.

Install it:

Upgrade your projects:

• Single project
  
  trac-admin /path/to/projenv upgrade
• All projects in /var/trac
  
  for project in /var/trac/*; do trac-admin $project upgrade; done

Restart Apache

Ran into major issues with conflicting versions of libexpat being used by Apache and Python:
I'm "pretty sure" the solution was not as complicated as all the rebuilding (mod_python, Apache, etc.) and what not that I did as those still left old expat files in /usr/local/apache2/lib. I think I just need to delete those.
Each project contains a copy of the Trac documentation in the wiki. To update the documentation files:

• Single project
  
  trac-admin /path/to/projenv wiki upgrade
• All projects in /var/trac
  
  for project in /var/trac/*; do trac-admin $project wiki upgrade; done